TextBox.AddParsedSubObject(Object) 方法

定义

重写以便只允许文本控件作为 Text 属性添加。

protected:
 override void AddParsedSubObject(System::Object ^ obj);
protected override void AddParsedSubObject (object obj);
override this.AddParsedSubObject : obj -> unit
Protected Overrides Sub AddParsedSubObject (obj As Object)

参数

obj
Object

一个 Object,表示已经过分析的元素。

例外

obj 的类型不是 LiteralControl

示例

下面的代码示例演示如何在自定义服务器控件中重写 AddParsedSubObject 方法,以便在分析的对象TextLiteral控件时,它始终将 属性设置为Text分析对象的 属性,否则会引发异常。

重要

此示例具有一个接受用户输入的文本框,这是一个潜在的安全威胁。 默认情况下,ASP.NET 网页验证用户输入是否不包含脚本或 HTML 元素。 有关详细信息,请参阅脚本侵入概述

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom TextBox - AddParsedSubObject - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - AddParsedSubObject - C# Example</h3>
            
            <aspSample:CustomTextBoxAddParsedSubObject 
              id="TextBox1" 
              runat="server">Hello World!
            </aspSample:CustomTextBoxAddParsedSubObject>
            
        </form>
    </body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom TextBox - AddParsedSubObject - VB.NET Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - AddParsedSubObject - VB.NET Example</h3>
            
            <aspSample:CustomTextBoxAddParsedSubObject id="TextBox1" 
             runat="server">Hello World!</aspSample:CustomTextBoxAddParsedSubObject>
        </form>
    </body>
</html>
using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxAddParsedSubObject : System.Web.UI.WebControls.TextBox
  {
    protected override void AddParsedSubObject(object obj)
    {
      // If the object is a LiteralControl, then set this control's Text property.
      if (obj is System.Web.UI.LiteralControl) 
      {
        this.Text = ((System.Web.UI.LiteralControl)obj).Text;
      }
      else 
      {
        throw new System.Web.HttpException("You cannot have a child control of type " + obj.GetType().Name.ToString());
      }
    }
  }
}
Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomTextBoxAddParsedSubObject
        Inherits System.Web.UI.WebControls.TextBox

        Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)

            ' If the object is a LiteralControl, then set this control's Text property.
            If TypeOf obj Is System.Web.UI.LiteralControl Then
                Me.Text = CType(obj, System.Web.UI.LiteralControl).Text
            Else
                Throw New System.Web.HttpException("You cannot have children controls of type " + obj.GetType().Name.ToString())
            End If
        End Sub
    End Class
End Namespace

适用于

另请参阅